It is conventional, in medical practice to ascertain the status and health of a human fetus by ultrasound. Typically a pregnant female may undergo 1 to 4 ultrasound examinations during her pregnancy. In addition, the heart of the fetus will be detected and monitored using a stethoscope. It is also conventional to monitor the heartbeat of a neonate (newly born infant) during and immediately after childbirth, using a stethoscope or a more sophisticated analysis instrument.
After childbirth, the status of pre-term neonates may also be ascertained using electroencephalography (“EEG”), which measures neurophysiological activity, which is essentially a pattern of electrical signals generated by the brain, known generally as brain waves. The EEG comprises a record of electrical rhythms and other electrical activity of the brain. EEG's are widely used to assist in the diagnosis, in children and adults, of epilepsy, brain tumors, physiological disorders and other brain abnormalities. An EEG examination may disclose and help diagnose brain abnormalities and injuries such as those described above because an injured or abnormal brain will produce electrical waves that differ in predictable ways from waves produced by a normal and healthy brain.
It has been thought to be very difficult to obtain meaningful brainwaves from fetuses because the fetal brain produces brain waves that are weaker than those of a child or an adult and the signals must traverse multiple layers of tissue that enclose the fetus (e.g., amniotic fluid, mother's layers of skin, muscle and blood).